OK, here's an odd question. I'm planning to build THE BIKE in 2011--you know, the one that will be perfect in every way so I can stop buying bikes

The Bryant has absolutely everything I want, except the smallest size is 49cm. I'm normally in the 46-47cm range. According to Civia's website, the closest dealer is nearly a 3 hour drive from me, so trying one out is not an option. Is it possible to build one of these up with 650b or 26" wheels, and if so, would it make much of a difference in standover height?
I guess I'm also basing this off the fact that my girlfriend has a 49cm Steamroller that's a tad too tall for me. But the top tube on the Bryant slopes gently, so it's possible it wouldn't be a problem...I don't know.